Food service tray

ABSTRACT

A food service tray made of polyurethane foam coated throughout its exterior with an epoxy, includes a base and cover, each having cavities therein in registry with cavities of the other for receipt of conventional dishware and flatware, each cavity having a perimetrical thermal barrier around it to minimize lateral heat transfer, each tray assembly having projections in its cover and recesses in its base facilitating stacking in vertical columns, one of the cavites in the cover being aligned with the lug projecting up from the top thereof, to facilitate stacking covers vertically, prior to mounting on bases, a reflective shield being provided in the facing surfaces of the base and cover.

United States Patent 1191 Douglas et al.

1451 Nov. 5, 1974 1541 F001) SERVICE .TRAY

[75] Inventors: Carl L. Douglas, 1220 Fox Hills Dr.,

Indianapolis, Ind. 46208; William J.

Evans, Indianapolis, Ind; Ronald J. Kiess, Greenfield, ind; Robert A.Sutton, 5030 E. Pleasant Run Pky., Indianapolis, Ind. 46201 [7 3]Assignees: Said Carl L. Douglas, by said Evans and Kiess; said Robert A.Sutton, by said Evans and Keiss, both of Indianapolis, Ind. partinterest to each [22] Filed: July 13, 1972 [2i] App]. No.: 271,546

52 us; (:1.... 220/21 206/4, 206/509, 220/9 F, 220/23.6 511 1m. (:1 865d1/24, B65d 21/02 [58] Field of Search 220/20, 9 F, 23.6, 23.8; 229/35MF; 09/183, 184, 185, 187, 188

[56] References Cited UNITED STATES PATENTS 2,695,115 11/1954Roop......L. 220/97 R x 3,049,277 8/l962 Shappell.... 229/35 MF3,305,l24 2/l967 Whiteford 220/23.8 X

Bridges 220/9 F X 3,586,201 6/1971 Ebert 220/97 R X 3,6l3,933 l0/l97lPilz 220/9 F X 3,684,633 8/1972 Hoose 220/9 F X 3,705,222 12/1972 Rogerset al 1 220/20 3,799,386 3/l974 Madalin et al. 220/9 F X PrimaryExaminer-William i. Price Assistant Examirkzw-Steven M. PollardAttorney, Agent, or Firm-Woodard, Weikart, Emhardt & Naughton [57]ABSTRACT A food service tray made of polyurethane foam coated throughoutits exterior with an epoxy, includes a base and cover, each havingcavities therein in registry with cavities of the other for receipt ofconventional dishware and flatware, each cavity having a perimetricalthermal barrier around it to minimize lateral heat transfer, each trayassembly having projections in its cover and recesses in its basefacilitating stacking in vertical columns, one of the cavites in thecover being aligned with the lug projecting up from the top thereof, tofacilitate stacking covers vertically, prior to mounting on bases, areflective shield being provided in the facingsurfaces of the base andcover.

2 Claims, 8 Drawing Figures PATENTEDNUV 51974 sum 10? 8 FOOD SERVICETRAY BACKGROUND OF THE INVENTION 1. Field of the Invention Thisinvention relates to thermally insulated containers, and moreparticularly to containers adapted to food and beverage services.

2. Description of the Prior Art There is a considerable amount of priorart in the field of insulated containers for food and beverage servicesand for other purposes. Specific examples of which we are aware in theissued patents are as follows:

3,107,027 Sheng-Chiao Hong Oct. I963 3,l l4,457 Knapp et :1]. Dec. l7.I963 3,295,737 Page et al. Jan. 3, I967 3,305.]24 Whitel'ord Feh. Zl,I967 3,305,]26 Cease Feb. 2i, I967 3,305,283 MacKay Feh. 2l. I9673.342.397 Duitsman Sept. I), I967 3,-LX63 Earl Sept. 17. I968 3,532,247Bridges Oct. 6, I970 3,6()l,277 Andrews ct al. Aug. 24. I971 3,608,770Naimoli Sept. 28, 197i Des. 219.204 Bridges et al. Nov. I7, I970 Whilethe foregoing references disclose various ways and means of insulatingtrays, stacking trays, and arranging recesses therein, none of them isbelieved to provide an optimum combination of features.

It is therefore a general object of the present invention to provide amethod and means of increasing the efficiency of food servicedepartment, by enabling the department to serve food and beverages atproper temperatures with fewer employees, more specifically implementedby a food service tray having insulating features and stacking featuresenablinglonger periods to be taken for food/tray assembly, and storage,and service to patients, in the health-care industry, guests in thehotel/motel industry, students in the school lunch programs, customersin the airline industry, and the like.

SUMMARY OF THE INVENTION Described briefly, in a typical embodiment ofthe present invention, there is a muIti-compartment insulated food andbeverage service tray incorporating a type of barrier or seal whichoccludes each food compartment opening, thus minimizing lateral (andvertical) transfer of heat from one compartment to another, and thusminimizing temperature change of the contents of any compartment over anextended period of time.

In the preferred embodiment, the user can place all food, beverages, andflatware for a complete meal within the confines of the tray, utilizingconventional sizes and shapes of permanent or disposable dishwater. Theheight, depth and length of the tray is such that it will fit instandard tray carts and in institutional dishwashers.

Stacking lugs areprovided to enable stacking the tray assemblies in,vertical columns, and also to enable stacking of covers conveniently,separate andapart from the tray bases. The shapes of the cover and baseis distinctive, making the correct orientation thereof readilyrecognized for convenience of assembly of the cover to the base, andenabling placement of the base and of the cover in the dish rack of aninstitutional dish washing machine, without tipping either the base orcover.

Both the base and cover are made of material having high thermalinsulation properties but having an exterior surface of suitabledurability and cleanability the entire unit being sufficientlytemperature resistant to avoid burning, and to avoid damage when exposedto the level of temperatures necessary for proper sterilization.

BRIEF DESCRIPTION OF THE DRAWINGS showing two tray assemblies stacked,with the cut-away portion showing an interlocking lug and socket.

FIG. 6 is an enlarged fragmentary section of the base showing recessesdisposed for reception of a menu clip.

FIG. 7 is anenlarged fragment of FIG. 4 showing the section through thethermal barrieror seal between the dinner plate compartment and soupbowl compartment at the point of nearest proximity of the onecompartment with the other compartment.

FIG. 8 is an elevational view of two stacked covers.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings indetail, the illustrated embodiment of the food service tray assembly asshown in FIG. 1 is generally rectangular in shape, but one corner isprovided with anangle as shown at 11, and this angle is provided ontheface 12 of the cover and face 13 of the base, as indicated morespecifically in the elevational view of FIG. 2. It facilitates quickrecognition of the correct orientation of the cover with respect to thetray, and, together with a feature described hereinafter, facilitatesplacement of the cover and of the base in the dish rack of institutionaltype dishwashing machines, without tipping.

The parting line 14 between the cover and base is also the line at whichthe conventional type of tray permits considerable lateral heat flowfromone compartment therein to another. The present invention hasprovisions for avoiding this, as will be described more fullyhereinafter.

Referring further to FIG. 1, along with FIG. 2, there is an upwardlyprojecting lug 16 on the top of the cover and another upwardlyprojecting lug 17 on the top of the cover, horizontally spaced fromlug'l6. Lug 16 has two legs 18 and 19 extending horizontally indifferent directions and in this embodiment, they are shown extending atwith respect to each other.

Another exterior surface feature of the cover is the stepped downportion 21 extending along the side of the tray at a lesser overallheight than the major area 22 of the top. Similarly, in the base of thetray there is a stepped up portion providing a surface23 closer to theparting line 14 than is the major area 24 of the bottom of the base.These features can be best appreciated by referring to FIG. 5. Itprovides a small enough thickness dimension (2 inches or less) to adaptthe tray and the cover to separately fit the dish racks of institutionaldishwashing machines. It also facilitates identification of one trayassembly from another in a stack, and also facilitates the separation ofone tray assembly from another in a stack by providing a fingerreceiving space 25 between each tray assembly and that next above it.

While referring to FIG. 5, it should be noted that the lug 16 on thecover of the lower tray assembly is received in a recess or socket inthe bottom of the base of the upper tray assembly. Similarly the lug 17of the cover of the lower tray assembly is received in a recess orsocket in the base of the upper tray assembly. This mating of lugs andsockets between the upper and lower members of succeeding trayassemblies facilitates secure stacking of made-up trays prior to,during, and subsequent to loading in a serving cart or the like.

Referring now to the top plan view of the base as shown in FIG. 3, thevarious cavities can be identified by reference letters as follows:

Dinner plate cavity Soup Bowl cavity Hot Beverage cavity Milk cartoncavity Juice Glass cavity Flatware cavity Bread cavity Condiment cavityl Salad cavity .l Dessert cavity A thermal barrier to lateral flow ofheat into or out of certain of these cavities is provided in the form ofa lip or bead completely surrounding the cavity. For example, for thedinner plate cavity A, there is a bead 26 projecting upwardly from thetop surface 27 at the parting line 14. The nature of this bead is bestshown in FIGS. 4 and 7. Typically this bead rises to a point one-quarterinch above the parting line and, as best shown in FIG. 4, it projectsinto cavity AA of the cover which is in registry with caviy A of thebase, and is in contact with the wall of the cavity AA completely aroundthe perimeter of the cavity. Thus it provides a perimetrical thermalbarrier preventing or at least mini mizing heat transfer laterally (inthe plane of the parting line 14) from or to the dinner plate cavitydefined by the registering cavities A and AA. This same type ofperimetrical thermal barrier is provided between the registeringcavities B and BB for the soup bowl cavity, registering cavities for thesalad, dessert, milk carton and juice glass. It can also be provided bythe registering cavities C and CC of the hot beverage cavity, ifdesired.

As shown in FIG. 4 and better shown in FIG. 7, at the location ofnearest proximity of the dinner plate compartment to the soup bowlcompartment, the bead 26 of the dinner plate cavity and the bead 28 ofthe soup bowl cavity, are disposed on opposite sides of the wall portion29 of the cover located between the dinner plate cavity and soup bowlcavity thereof. The overlapping faces of the lips and wall are inoccluding relationship, not only minimizing or precluding lateral heattransfer between cavities, but also minimizing or preeluding lateraltransfer of air, vapors and the like from one cavity to the next.Accordingly there is no intermixing of flavors of the contents of thetray assembly.

As mentioned above, the covers can be stacked separately, prior toassembly thereof with the trays. In this connection a comparison can bemade of the location of the lug 16 in the cover of FIG. 1, and thelocation of the corner 31 in the bread cavity of the base. The cover hasa bread cavity in registry with the cavity G of the base. The insidefaces 34 and 36 (FIG. 8) of the corner of the bread cavity in the cover,are in vertical alignment with the inside faces 32 and 33 respectivelyof the corner 31 of the bread cavity in the base, and these are invertical projection with the outside faces of the legs 18 and 19 of thelug 16 in the cover. Therefore it will be recognized that when onecorner is placed on top of another cover, the lug in the top of thecover below will be received in the bread cavity corner of the coverabove and thereby provide for vertical stacking of the covers withrespect to one another. Similarly the cover has a recess in theunderside thereofimmediately under the lug 17 thereof to receive the lugof a cover immediately below it when the covers are stacked together.Thus a stable stack of covers can be provided. This is represented inFIG. 8 by way of example. When the covers are stacked, the outer face ofthe leg 19 of the lug 16 is piloting on the wall 36 of the bread cavityGG in the cover, and the outer face of the leg 18 of the lug is pilotingon the face 34 of the corner in the cavity GG of the cover.

As shown in FIG. 6, the edge of the base has a recess at 37 thereinadjacent the bottom, and a recess at 38 therein adjacent the top surfaceat the parting line 14. These recesses are adapted to receive the lugs39 and 41, respectively of a menu clip 42, facilitating attachmentthereof to the base.

The material employed throughout the base and cover must have goodinsulating qualities, durability, smooth and sanitary and durablesurfaces, resistance to damage from heat under sterilizing temperatures,non flammability, light weight and low cost. An example of a materialexhibiting such characteristics is a polyurethane rigid closed cellfoam. Desirable characteristics of such material are a density of fourto eight pounds per cubic foot, tensile strength of 90 to 250 pounds persquare inch, compression strength at ten percentdeflection of to 275pounds per square inch, maximum service temperature of 320 Fahrenheit, athermal conductivity of 0.15 to 0.2] Btu per square foot per hour perdegree Fahrenheit per inch, a coefficient of linear expansion of 4 X 10inches per inch per degree Fahrenheit, a dielectric constant of 1.10,and a dissipation factor at 28C of 0.001 8. It also should havecharacteristics of self extinguishing in the event of application of ablaze thereto and, as specified by the ASTM Standard Dl692-59T, it wouldqualify as burnable but selfextinguishing when compounded.

As examples of sizes of the compartments, the dinner plate cavity wouldtypically be 9 inches in diameter or slightly greater than that toaccommodate all standard dinner plates up to 9 inches in diameter. Thesoup bowl compartment is large enough to accommodate all l0 ounceconventional soup bowls and is 6.54 inches in diameter or slightlygreater. The milk compartment is large enough to accommodate onehalf-pint milk carton. The juice compartment will accommodate four ounchjuice glasses. The salad compartment will accommodate all conventionalsix inch diameter round salad plates, and is 6.47 inches in diameter orslightly greater. The dessert'compartment will accommodate standardinstitutional dessert dishes and is 4.92 inches in diameter or slightlygreater. The diameters are given at the level of greatest diameter inthe compartment. Typically the stacking lugs would 3 /2 inches long forlugs 17, five/sixteenth inch wide and one quarter inch high. The chevronshaped stacking lug 16 would be of similar dimension.

The foam material has been described above. preferably it is coated onthe exterior by an epoxy coating. Although a coating comprising a singlecoat of epoxy (sprayed on, for example) may be suitable, a coatingcomprising at least two coats is preferred. This is best represented inFIG. 7 where the outermost coating 43 facing the cavities is atransparent epoxy. This covers a heat shield or reflective shield 44which covers the first epoxy coating 46. On the bottom of the base andon the top of the cover, there need be only one or two coats of epoxythe first coat possibly containing the color, and the outer coatbeingclear. The radiation shield is a shiny metallic layer which may beapplied by vacuum metallizing electro-plating, metallic painting,stamped sheet foil, a polyester film or other film coated with aluminum.As suggested above, the shield would be placed directly on the epoxybase coat and not directly on the foam. It will be noted from thevarious illustrations, that there is both a thickness of the foammaterial and the reflective barrier or shield, between the top of eachcavity in the cover and the outside top of the cover, and between thebottom of each cavity in the base and the outside bottom face of thebase. Thus the present invention is well adapted not only to minimizinglateral heat transfer, but also to minimize vertical heat transfer.

While the invention has been disclosed and described in some detail indrawings drawwings and foregoing description, they are to be consideredas illustrative and not restrictive in character,'as other modificationsmay e. each of said cavities of said cover being in registry with one ofsaid cavities in said base to form a food storage compartment;

-f. said cover and base having mating perimetrical thermal barriersaround certain of said registering cavities, to inhibit lateral heattransfer between adjacent cavities;

g. said coaver having means to inhibit vertical heat release from saidfood storage compartments;

h. the overall height of said assembly being less for a distance alongat least one margin thereof than elsewhere to provide, in a stack ofassemblies, finger receiving spaces between each assembly and theassembly next below it, and to facilitate reception of said cover andsaid base separately in the dish rack of an institutional dishwashermachine; and

. wherein one side of said assembly is irregular with respect to theothers to facilitate identification of correct registry of said coverwith said base in assembly thereof; said cover having lug meansprojecting upward therefrom, and said base having upwardly extendingrecess means therein,

whereby said assembly is securely stackable with like assemblies, thelug means of said cover projecting into the recess means of the base ofthe assembly next above it, and the recess means of said base receivingthe projecting lug means of the cover below it;

one of said cavities in said cover having a corner therein disposed invertical projection with a corner in said one lug, whereby a pluralityof covers i like said cover isstackable, with the upwardly projectingone lug of each received in the corner of a cavity of the cover nextadjacent thereto.

2. The assembly of claim 1 wherein:

the horizontally spaced lugs are confiningly receivable in recesses in alike cover of another tray assembly.

1. A food service tray assembly comprising: a. a base, said basecomprising a urethane foam shape of a polyurethane rigid closed cellfoam, said shape having at least one coating all over the exterior ofthe foam; b. a cover different from said base and mounted on top of saidbase; said cover comprising a urethane foam shape of a polyurethanerigid closed cell foam, said shape having at least one coating all overthe exterior of the foam; c. said base having a plurality of cavitiestherein, said cavities being of a size and shape to accommodateconventional sizes and shapes of permanent and disposable dishware; d.said cover having a plurality of cavities therein; e. each of saidcavities of said cover being in registry with one of said cavities insaid base to form a food storage compartment; f. said cover and basehaving mating perimetrical thermal barriers around certain of saidregistering cavities, to inhibit lateral heat transfer between adjacentcavities; g. said coaver having means to inhibit vertical heat releasefrom said food storage compartments; h. the overall height of saidassembly being less for a distance along at least one margin thereofthan elsewhere to provide, in a stack of assemblies, finger receivingspaces between each assembly and the assembly next below it, and tofacilitate reception of said cover and said base separately in the dishrack of an institutional dishwasher machine; and i. wherein one side ofsaid assembly is irregular with respect to the others to facilitateidentification of correct registry of said cover with said base inassembly thereof; said cover having lug means projecting upwardtherefrom, and said base having upwardly extending recess means therein,whereby said assembly is securely stackable with like assemblies, thelug means of said cover projecting into the recess means of the base ofthe assembly next above it, and the recess means of said base receivingthe projecting lug means of the cover below it; one of said cavities insaid cover having a corner therein disposed in vertical projection witha corner in said one lug, whereby a plurality of covers like said coveris stackable, with the upwardly projecting one lug of each received inthe corner of a cavity of the cover next adjacent thereto.
 2. Theassembly of claim 1 wherein: the horizontally spaced lugs areconfiningly receivable in recesses in a like cover of another trayassembly.